From: Oleg Nesterov <oleg@redhat.com> stable inclusion from stable-v5.10.221 commit 82c7acf9a12c9b4e4b0aba531de82b4e39a345c8 category: bugfix bugzilla: 189268 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 7fea700e04bd3f424c2d836e98425782f97b494e ] kernel_wait4() doesn't sleep and returns -EINTR if there is no eligible child and signal_pending() is true. That is why zap_pid_ns_processes() clears TIF_SIGPENDING but this is not enough, it should also clear TIF_NOTIFY_SIGNAL to make signal_pending() return false and avoid a busy-wait loop. Link: https://lkml.kernel.org/r/20240608120616.GB7947@redhat.com Fixes: 12db8b690010 ("entry: Add support for TIF_NOTIFY_SIGNAL") Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Rachel Menge <rachelmenge@linux.microsoft.com> Closes: https://lore.kernel.org/all/1386cd49-36d0-4a5c-85e9-bc42056a5a38@linux.micro... Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Tested-by: Wei Fu <fuweid89@gmail.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Cc: Allen Pais <apais@linux.microsoft.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Joel Granados <j.granados@samsung.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Mike Christie <michael.christie@oracle.com> Cc: Neeraj Upadhyay <neeraj.upadhyay@kernel.org> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Zqiang <qiang.zhang1211@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Wang Hai <wanghai38@huawei.com> Signed-off-by: Chen Ridong <chenridong@huawei.com> --- kernel/pid_namespace.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index c290d21b6c24..5ce974421a83 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -222,6 +222,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns) */ do { clear_thread_flag(TIF_SIGPENDING); + clear_thread_flag(TIF_NOTIFY_SIGNAL); rc = kernel_wait4(-1, NULL, __WALL, NULL); } while (rc != -ECHILD); -- 2.34.1